(1) Theoretical Nuclear Physics

(2) Many-body systems interacting by random interactions

(3) Nucleon pair approximation of the shell model

(4) Systematics of nuclear properties

Professor Zhao received his Ph.D. in Physics in 1995 from Nanjing University. He had Science and Technology Agent (STA) fellow, Collaborating researcher, and Japanese Society of Promotion of Science (JSPS) fellow at RIKEN, Japan, and visiting scientist, Bartol Research Institute, University Delaware, USA.

 

Many-body systems interacting by random interactions: My collaborators and I worked very hard on the origin of the interesting observation of robustness of angular momentum zero ground states in many-body systems. I related the probability of any angular momentum J ground state probabilities with the times a certain J to be the lowest if only one term of two-body interactions is -1.This approach is found to be applicable to universal cases. We disproved a very popular idea that 0 g.s. is independent of forces used, and found they comes from certain interactions. We also studied the properties of the average energies, the generic rotation in fermion systems, etc. In recent years my students and I made contributions to evaluation of eigenvalues of random Hamiltonians.

Nucleon pair approximation of the shell model: My main contributions to this subject include: a) I find an efficient method to calculate the shell model hamiltonian within coupled nucleon pair basis.This method is a unified for both even and odd systems.b) I studied the validity of SD pair truncation, the application to realistic nuclei, validity of the FDSM etc. c) Another contribution is that the truncation scheme using pairs and the interactions between particles were found to be entangled. Recently we applied our formulation to describe low-lying states of medium-heavy nuclei in the transitional region.

Systematics of Nuclear properties: One of my contributions to this subject is that I constructed a simple way to take the "effective" boson numbers. I used those number to explore the nuclear systematics by NnNp which was firstly given by Rick Casten and Zamfir. Some ambiguities are clarified by constructions of the np interactions. Later in collaboration with my colleagues I realized that the NpNn scheme is actually applicable to even-even, even-odd, odd-even, and odd-odd nuclei. We noticed some anomalous deformation for N=104 isotones, etc.

1.  Physics Reports, Vol. 400, Page 1 (2004)

2.  Physical Review C66, 034304 (2002)

3.  Physical Review Letters, Vol. 85, 720 (2000)

4.  Physical Review C62, 014304 (2000)

5.  Physical Review C76, 054305 (2007)

6.  Physical Review C71, 047304 (2005)